1. Field of the Invention
The present invention relates to a noise isolation sheet provided to cover a panel, e.g., a door inner panel that is installed inside an automobile door.
2. Description of the Prior Art
As illustrated in FIG. 3, according to a known method of insulating noise in the interior of a door 60, a felt 2 or urethane is attached to the backside of an interior door trim 1 which is provided to the inner side of a door inner panel, or an article made from urethane is attached to the inner side of the door inner panel.
For example, the examined utility model application publication No. H5-23376 discloses a door trim which is provided with a pad material made of urethane foam and the like. The published patent application No. H10-119159 discloses a noise isolation cover made of urethane foam.
However, according to the above-described publications, the noise insulating effect is not satisfactory, because the felt 2, urethane, pad material and isolation cover are all made independently and are installed only partially to the side of the door trim 1 or the inner side of the door inner panel.
Further, the noise insulating members according to these publications are only partially installed, which causes the installation operation to be troublesome.
Concerning the above-mentioned problem, the assignee of the present invention previously provided a structure, as shown in FIGS. 4-6, wherein an isolation sheet 20 is provided between a door inner panel 11 and a door trim 12 and wherein the top end of the sheet 20 is secured to an inner weather strip 15 just like a curtain hanging from the upper part to the lower part of the door interior (See Japanese patent application No. 2002-57777).
In this structure, the inner weather strip 15 is composed of an installation base 16, seal lip portions 17 and 18, which are provided such that seal lip portion 17 is above seal lip portion 18, for elastically making contacts, from the inner side, with a door glass 70 which slides in the upward and downward directions, and a support portion 19 which extends downwardly from the installation base 16 for supporting the seal lip portions 17 and 18. A plurality of lip portions 16a and position adjustment protrusions 16b are provided on the upper surface of the installation base 16. The installation base 16 is inserted into a concave portion 13 formed on the upper portion of the door trim 12, while each of the position adjustment protrusions 16b makes contact with a corresponding step portion 13a on an interior of the concave portion 13 to position the installation base properly. The door trim 12 is fixed to a door inner panel 11 with clips 50.
According to this structure, two spaces X and Y are created between the door inner panel 11 and door trim 12 by the isolation sheet 20, so that the noise insulating effect improves compared to the conventional noise insulation mechanism, in which a felt, urethane, pad material, noise isolation cover and the like are used. Further, the noise isolation sheet 20 is provided by merely hanging the sheet 20 from the upper part to the lower part of the door interior, so that an installation operation is easy.
However, according to the prior art comprising the noise isolation sheet 20, water may invade from the outside of a car. Further, it is desired to produce a noise isolation sheet having better noise insulating and waterproofing functions.
Therefore, it is an object of the present invention to provide a noise isolation sheet which substantially prevents of water from invading from the outside of a car, and to improve a noise insulating property by restraining the outside noise from invading into the interior of a car as well as the interior noise from leaking outside of the car, in comparison with the prior art.